Dust on rear wheel on drivebelt side
 

Sorry to be a pain. I've had my fat bob now for 4 days, and its done about 250 miles. I'm noticing some small black particles on the rear wheel on the same side as the drive belt. The only thing I can think is it is actually coming from the belt. Is this normal? If not from the drive belt what could it be... I cant imagine its break dust since the other side of the wheel is pretty clean.

Have to say I'm absolutely loving the bike. Wish I'd bought one soooner....

I believe that might be some accumulated dirt from those hard 250 miles the bike has. That happens. :)

I agree that it just could be ordinary dirt. My rims are like magnets for the stuff. Clean 'em and see what happens. You also might want to inspect the full inside length of the drive belt for any signs of material coming off, make sure the belt is at the right tension. You're under warranty, have the dealer look at it if you're not sure.
And congrats on the bike.